title: Mice selectively bred for High and Low fear behavior show differences in the number of pMAPK (p44/42 ERK) expressing neurons in lateral amygdala following Pavlovian fear conditioning.
abstract: Individual variability in the acquisition, consolidation and extinction of conditioned fear potentially contributes to the development of fear pathology including posttraumatic stress disorder (PTSD). Pavlovian fear conditioning is a key tool for the study of fundamental aspects of fear learning. Here, we used a selected mouse line of High and Low Pavlovian conditioned fear created from an advanced intercrossed line (AIL) in order to begin to identify the cellular basis of phenotypic divergence in Pavlovian fear conditioning. We investigated whether phosphorylated MAPK (p44/42 ERK/MAPK), a protein kinase required in the amygdala for the acquisition and consolidation of Pavlovian fear memory, is differentially expressed following Pavlovian fear learning in the High and Low fear lines. We found that following Pavlovian auditory fear conditioning, High and Low line mice differ in the number of pMAPK-expressing neurons in the dorsal sub nucleus of the lateral amygdala (LAd). In contrast, this difference was not detected in the ventral medial (LAvm) or ventral lateral (LAvl) amygdala sub nuclei or in control animals. We propose that this apparent increase in plasticity at a known locus of fear memory acquisition and consolidation relates to intrinsic differences between the two fear phenotypes. These data provide important insights into the micronetwork mechanisms encoding phenotypic differences in fear. Understanding the circuit level cellular and molecular mechanisms that underlie individual variability in fear learning is critical for the development of effective treatment of fear-related illnesses such as PTSD.
authors.affiliation: Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Coyner
authors.affiliation: Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: McGuire
authors.affiliation: Department of Human Genetics, University of Chicago, IL, USA.
authors.forename: Clarissa C
authors.initials: CC
authors.lastname: Parker
authors.affiliation: Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Center for the Study of Traumatic Stress (CSTS), Bethesda, MD, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ursano
authors.affiliation: Department of Human Genetics, University of Chicago, IL, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, IL, USA.
authors.forename: Abraham A
authors.initials: AA
authors.lastname: Palmer
authors.affiliation: Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Center for the Study of Traumatic Stress (CSTS), Bethesda, MD, USA. Electronic address: LukeJohnsonPhD@gmail.com.
authors.forename: Luke R
authors.initials: LR
authors.lastname: Johnson
mesh_terms: D000818:Animals; D066272:Basolateral Nuclear Complex / Q000166:cytology / Q000201:enzymology*; D001522:Behavior, Animal / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D008297:Male; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology*; D010641:Phenotype; D011897:Random Allocation
chemical_list: D048052:Mitogen-Activated Protein Kinase 3
keywords: Anxiety; ERK; Fear and stress; MAPK; Microanatomy; PTSD; Resilience; Susceptibility